Snowdrops, bluebells and longer days can only mean one thing...

It's spring!

Here at Planet Science, we're getting very excited about spring. We love the longer days, watching the birds in the garden and all the flowers.

But why does spring happen?

The vernal equinox marks the beginning of spring. At the vernal equinox, the sun appears to be directly over Earth's equator, and the lengths of the day and the night are equal over most of the planet.

The seasons change because the axis of the Earth is tilted. In winter we are leaning away from the sun. As we travel around the sun we begin to lean towards the sun and it becomes first spring, then summer. This video tells you more:

Have a look at Four Seasons to find out more about science behind the seasons.